• Journal of Korea Multimedia Society
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• v.9 no.5
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• pp.671-680
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• 2006

As a mathematical technique with which we can find the minimum duration time needed to fire all the transitions at least once and coming back to the initial marking in a timed net, the minimum cycle time method has been widely used in computer system analysis. A timed net is a modified version of a Petri net where a transition is associated with a delay time. A delay time used in a timed net is a constant even though the duration time associated with an event in the world is a stochastic number in general. In the consequence, the result of minimum cycle time analysis is not realistic. Therefore, we propose ‘Stochastic Timed Net' where a transition can be associated with a stochastic number and introduce a minimum cycle time analysis method for ‘Stochastic Timed Net’ As an example of the application of ‘Stochastic Timed Net’, we introduce a ‘Stochastic Timed Net' model of a Location Based Service Providing Multimedia System and the result of minimum cycle time analysis of it. Whereas the typical form of the result of the existing minimum cycle time analysis is 'It takes at least 10 time units', the typical form of the result of minimum cycle time analysis of a ‘Stochastic Timed Net' is in the probability form such as "The probability of the events in which it finishes its job within 10 time units is 85%."

• Journal of Korea Multimedia Society
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• v.9 no.11
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• pp.1503-1514
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• 2006

Today, consumers can access Internet from everywhere, therefore most commercial and other organizations provide their services on the Web. As the result, countless Web service systems are already on the Internet and more systems are under construction. Therefore, many researches of verifying that the system to be constructed will not have any deadlock and will run successfully without any problem at the early stage of design have been performed. Several Petri net based verification methods have also been published. However, they have focused on building Petri net models of Web service systems and none of them introduces efficient analysis methods. As a mathematical technique with which we can find the minimum duration time needed to fire all the transitions at least once and coming back to the initial marking in a timed net, the minimum cycle time method has been widely used in computer system analysis. A timed net is a modified version of a Petri net where a transition is associated with a delay time. A delay time used in a timed net is a constant even though the duration time associated with an event in the real world is a stochastic number in general. Therefore, this paper proposes 'Mixedly Distributed Stochastic Timed Net' where a transition can be associated with a stochastic number and introduce a minimum cycle time analysis method for 'Mixedly Distributed Stochastic Timed Net'. We also introduce a method of analysing a Web service system's response time with the minimum cycle time analysis method for 'Mixedly Distributed Stochastic Timed Net.'.

• The Transactions of the Korea Information Processing Society
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• v.5 no.5
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• pp.1119-1129
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• 1998

This paper proposes a method to estimate the time to execute a hypermedia scenario. The method builds a PNDT(Petri Net with probability Distribution Table) model for the flow of the scenario, then performs Monte Carlo Simulation on the PNDT model to estimate the duration time from the start to the end of the scenario. The estimated times to execute scenarios are useful to both information providers and users. A user can make a better time plan referring to them, and an information provider can make the most efficient scenario-presentation schedule for users referring to them. However, no research results regarding this subject have been reported yet.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.141-143
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• 1998

본 논문은 멀티미디어 시나리오 수행시간 예측 방법을 제안한다. 제안된 방법은 멀티미디어 시나리오를 확률분포표를 갖는 페트리넷(Multimedia Petri Net with probability Distribution Table: MPNDT)으로 모델링하고, MPNDT 모델에서 시나리오의 흐름을 시뮬레이션하여 시작부터 종료에 이르기까지의 수행시간을 계산하다. 사용자는 이를 참조하여 시간 사용 계획을 세울 수 있고 , 멀티미디어 정보제공자는 이를 참조하여 사용자에게 가장 효율적인 감상 스케쥴을 작성하여 줄 수 있다.